Gokce K Atac | T.C. Ufuk University (original) (raw)

Papers by Gokce K Atac

Türk radyoloji dergisi, May 26, 2016

Bu çalışma 36. Ulusal Radyoloji Kongresi'nde sözel bildiri olarak sunulmuştur,

DergiPark (Istanbul University), Dec 31, 2021

Kantitatif bilgisayarlı tomografinin kronik obstrüktif akciğer hastalığı fenotipi belirlemedeki r... more Kantitatif bilgisayarlı tomografinin kronik obstrüktif akciğer hastalığı fenotipi belirlemedeki rolü The role of quantitative computed tomography in determining the phenotype of chronic obstructive pulmonary disease ÖZET Amaç: Kronik obstrüktif akciğer hastalığı tanısı konmuş hastalarda, kantitatif toraks bilgisayarlı tomografi (BT)'nin KOAH fenotiplerinin belirlenmesindeki rolünü araştırmaktır. Materyal ve Metodlar: Ocak 2007-Eylül 2013 tarihleri arasında Ufuk Üniversitesi Dr. Rıdvan Ege Hastanesi Göğüs Hastalıkları polikliniği/ servisinde değerlendirilen 104 hasta ve 20 kontrol olgusu çalışmaya alındı. Hastaların spirometrik parametrelerine SFT kayıtlarından, toraks BT verilerine ise Radyoloji arşivinden ulaşıldı. Tüm toraks BT'lerin kantitatif incelemesi Radyoloji Anabilim Dalında belirlenen tek bir Radyoloji Uzmanı tarafından yapıldı. Görüntü Arşivleme ve İletişim sisteminden elde edilen toraks BT incelemeleri Radyoloji servisinde kullanılan iş istasyonuna yüklendi. Bu amaçla Adwanced Workstation 4.2 Sun Workstation kullanıldı. Bulgular: Çalışmamızda sağ ve sol akciğer amfizem hacimleri ortalama değerleri sırasıyla 205,8±303,3 ml ve 210,3±363,8 ml olup kontrol grupları ile aralarında anlamlı bir fark bulundu (p<0,001). Olguların ROC analizinden elde edilen amfizem hacmi eşik değeri %2,1 olarak alındığında, FEV1/FVC <%70'in altında olma durumunu tahmin etmedeki duyarlılığı %62,3, seçiciliği %94,4, pozitif prediktif değeri ise %98,5 olarak bulundu. Kronik bronşit ise direk bronş duvar kalınlığı ölçümleriyle bir cutoff belirlenemedi. Katılımcıların spirometri değerleri incelendiğinde kronik bronşitlilerin (n=39) FEV1, FEV1/FVC ve FEF 25-75 değerleri amfizemli olgularınkinden (n=65) anlamlı olarak yüksek bulunmuştur (p<0,05). Spirometri değerlerinden, YÇBT'deki amfizem yüzdesi ile en yüksek negatif korelasyon gösteren parametre FEV1/FVC idi (r=-0,539) (p<0,001). Diğer spirometri değerlerinin aksine FEV1/FVC (%) değeri ile bronş duvar kalınlığı arasında negatif korelasyon izlendi (r=-0,214) (p<0,05). Sonuç: Kantitatif BT'de amfizem ve kronik bronşit varlığının fonksiyonel değerlendirme sonuçlarını öngördüğü ancak, yıllık atak sayısı ve semptom skorları açısından belirleyici olmadığı izlenmiştir. Ayrıca kantitatif BT'de amfizem hacmi eşik değeri %2,1 olarak bulundu. Radyolojik bulguların klinikle korelasyonu değerlendirilip fenotip belirlenmesi için ileri araştırmalara ihtiyaç vardır.

2020 Medical Technologies Congress (TIPTEKNO), 2020

Thyroid tumors frequently observed disease by using medical imaging methods. Ultrasonography is t... more Thyroid tumors frequently observed disease by using medical imaging methods. Ultrasonography is the most frequently performed method for diagnosis. To determine, tumor is benign or malign, experienced doctors use various techniques. Fine needle aspiration biopsy and follow-up checking are used for determining type of tumor. However, these methods are time consuming and increasing work load of doctors. So, they created a risk stratification system which has called as ACR-TIRADS. Downside of this system is being subjective and for multiple tumors, it will be time consuming due to analyzing multiple features. To ease, doctors work load and help them to obtain more objective classification, on this study we worked thyroid tumors with texture analysis methods and tried to classify them, to their TIRADS classes. As the result of this study, sensitivity found up %82.8, precision %85 and accuracy found up %73.0.

Ulcerative colitis is an inflammatory bowel disease. In addition to intestinal symptoms such as b... more Ulcerative colitis is an inflammatory bowel disease. In addition to intestinal symptoms such as bloody diarrhea, abdominal pain, and weight loss, various extraintestinal complications may be encountered. Thromboembolic events rarely complicate ulcerative colitis. Herein, we present a case of established ulcerative colitis, which was complicated with acute mesenteric ischemia, deep vein thrombosis, and pulmonary thromboembolism

TURKISH JOURNAL OF MEDICAL SCIENCES, 2019

Background/aim: Sonographic assessment of diaphragm structure and function would be a useful clin... more Background/aim: Sonographic assessment of diaphragm structure and function would be a useful clinical tool in patients with chronic obstructive pulmonary disease (COPD). Our aim was to determine the muscle thickness of the diaphragm and the usefulness of clinical practice in patients with COPD. Materials and methods: The diaphragmatic thickness of 34 COPD patients and 34 healthy subjects was measured during tidal volume (Tmin) and deep inspiration (Tmax) on both sides using a B-mode ultrasound. The body mass index and the modified Medical Research Council (mMRC) index values were reported. Results: There was no correlation among TminR (P = 0.134), TminL (P = 0.647), TmaxR (P = 0.721), and TmaxL (P = 0.905) between the patients with COPD and the control group. There was also no significant difference between diaphragmatic thickness and COPD severity, respiratory function (P = 0.410), and frequency of exacerbations (P = 0.881) and mMRC (P = 0.667). Conclusion: Diaphragmatic dysfunction in COPD is related to mobility restriction rather than muscle thickness.

Emergency Radiology, 2016

The value of abdominal computed tomography in non-traumatic abdominal pain has been well establis... more The value of abdominal computed tomography in non-traumatic abdominal pain has been well established. On the other hand, to manage computed tomography, appropriateness has become more of an issue as a result of the concomitant increase in patient radiation exposure with increased computed tomography use. The purpose of this study was to investigate whether C-reactive protein, white blood cell count, and pain location may guide the selection of patients for computed tomography in non-traumatic acute abdomen. Patients presenting with acute abdomen to the emergency department over a 12-month period and who subsequently underwent computed tomography were retrospectively reviewed. Those with serum C-reactive protein and white blood cell count measured on admission or within 24 h of the computed tomography were selected. Computed tomography examinations were retrospectively reviewed, and final diagnoses were designated either positive or negative for pathology relating to presentation with acute abdomen. White blood cell counts, C-reactive protein levels, and pain locations were analyzed to determine whether they increased or decreased the likelihood of producing a diagnostic computed tomography. The likelihood ratio for computed tomography positivity with a C-reactive protein level above 5 mg/L was 1.71, while this increased to 7.71 in patients with combined elevated C-reactive protein level and white blood cell count and right lower quadrant pain. Combined elevated C-reactive protein level and white blood cell count in patients with right lower quadrant pain may represent a potential factor that could guide the decision to perform computed tomography in non-traumatic acute abdomen.

Journal of Medical Imaging and Health Informatics, Mar 1, 2021

Background: Computed tomography perfusion (CTP) images include more noise than routine clinic com... more Background: Computed tomography perfusion (CTP) images include more noise than routine clinic computed tomography (CT) images. Singular value decomposition based deconvolution algorithms are widely used for obtaining several functional perfusion maps. Recently block circulant singular value decomposition algorithms become popular for its superior property of immunity to contrast bolus lag. It is well known from literature that these algorithms are very sensitive to noise. There are a lot of examples of noise reduction filters in the literature as well as commercial ones. Functional maps which help physicians in the diagnostic process can be obtained with better image quality by de-noising CTP images with adaptive noise reduction filters. Objective: In this study, the effect of a noise adaptive wavelet filtering method on diagnostic performance on CTP stroke patient images is investigated. Method: Images of acute stroke patients were de-noised by this method and their diagnostic value were evaluated by visual means, peak signal-to-noise ratio and time intensity profile metrics. An observer evaluation study was carried out in order to validate quantitative image quality metrics. The results are compared with Gaussian and a bilateral filter based filtering method called TIPS (Time Intensity Profile Similarity) on same images sets to benchmark proposed method. Results: The diagnostic value of the images obtained from noise adaptive wavelet filtering method were better than Gaussian filter method and were compatible with a wellknown time intensity profile similarity bilateral filter method. Diagnostic performance of the both observers were improved compared to both Gaussian and TIPS methods. Conclusion: The noise adaptive wavelet filter method succeeded to reduce noise while preserving details contained in the contrast bolus. Its final effect on the timeintensity profiles and generated perfusion maps are compatible with the literature and showed improvements on diagnostic performance on specificity and overall accuracy when compared to other methods.

Turkish journal of trauma & emergency surgery, 2017

BACKGROUND: We aimed to determine the attitudes and practices of emergency physicians (EPs), neur... more BACKGROUND: We aimed to determine the attitudes and practices of emergency physicians (EPs), neurosurgeons, and radiologists in Turkey regarding computed tomography (CT) use for adults with minor head injury (MHI). METHODS: This cross-sectional study was conducted between August 2015 and October 2016 after obtaining the approval of the institutional ethical committee. The purpose of this study was disclosed to the participants prior to beginning the survey. The study was performed conducting a questionnaire via e-mail on three groups of participants including EPs, neurosurgeons, and radiologists. Participants comprised academic staff at university hospitals as well as department chiefs, specialists, and residents working at university, government, and private hospitals, all of whom are in charge of evaluating MHI patients. RESULTS: A total of 607 participants including 201 (33.1%) EPs, 179 (29.5%) neurosurgeons, and 227 (37.4%) radiologists responded to the survey; 31% of the participants reported awareness and 27.3% reported use of head CT rules in MHI. Awareness and use of the rules were most prominent in EPs group, while the lowest rates were observed in radiologists group (p<0.01). The leading factors inhibiting the use of head CT rules in MHI stated by EPs were medicolegal anxiety (73.6%), expectations of patients and/or patient relatives (72.6%), and time constraints (44.3%). The leading factors stated by neurosurgeons were medicolegal anxiety (60.9%) and expectations of patient and/or patient relatives (46.4%); "not being consulted in the decision-making process to obtain CT in MHI" (65.6%) and medicolegal anxiety (49.8%) were the leading factors stated by radiologists. CONCLUSION: The results of our study show that many physicians in Turkey do not have favorable attitudes regarding head CT rules in MHI. Medicolegal anxiety, expectations of patient and/or patient relatives, time constraints, wide availability of CT, and lack of adequate education on radiation protection or on patient dose from imaging are the common reasons for this practice pattern.

Case reports in radiology, 2015

Adult intussusception is a rare entity accounting for 1% of all bowel obstructions. Unlike intuss... more Adult intussusception is a rare entity accounting for 1% of all bowel obstructions. Unlike intussusceptions in children, which are idiopathic in 90% of cases, adult intussusceptions have an identifiable cause (lead point) in the majority of cases. Crohn's disease (CD) may affect any part of the gastrointestinal tract, including the appendix. It was shown to be a predisposing factor for intussusception. Here, we report a rare case of adult intussusception with a lead point, emphasizing diagnostic input of multidetector computed tomography (MDCT) in a patient with active CD that involves the appendix.

Turkish Journal of Medical Sciences, Aug 30, 2021

Introduction Thoracic outlet syndrome represents a complex of signs and symptoms due to compressi... more Introduction Thoracic outlet syndrome represents a complex of signs and symptoms due to compression of neurovascular structures in cervico-thoracic area. Three anatomical locations responsible for the compression of neurovascular structures include inter-scalene space, costo-clavicular space, and retro-pectoralis minor space [1]. Various abnormalities originating from ribs or scalene muscles and trauma to this area can narrow these spaces and results in compression of neurovascular structures. There are 3 different types of thoracic outlet syndrome (TOS), which are classified according to the trapped anatomical structure and clinical symptoms resulting in neurogenic, arterial and venous TOS [2]. Neurogenic TOS composes approximately 90% of TOS cases. It is more difficult to diagnose since there is no definitive neurodiagnostic testing and objective criteria for the diagnosis of TOS [3]. In spite of the treatment of patients with arterial or venous TOS is clear, treatment of patients with neurogenic TOS is the subject of continuing controversy. Surgical results vary, with patients reporting good or excellent results in 53% to 92% of cases [4,5]. In this study, the volumetric measurement of interscalene space was done in cadavers and this information was then transferred to clinical situation of TOS and the data were analyzed for the potential use in diagnosis and treatment selection. 2. Materials and methods 2.1. The first phase of the study In the first phase of the study 16 cervical dissections were performed in 8 formalin-fixed cadavers. Dissections were made in supine anatomical position of cadavers. First an Background/aim: The aim of this study was to measure the volume of interscalene space in thoracic outlet region on cadavers and radiological images and to analyze the potential value of these measurements in diagnosis and treatment of thoracic outlet syndrome (TOS). Materials and methods: The dimensions of the anterior interscalene space in 8 formalin-fixed human cadavers were studied by direct measurement and additionally evaluation of the volume of this space were done by using mold and volume calculation formula of square pyramid, due to resembling a pyramid. In the second phase of this study, interscalene space volume was calculated by formula and compared to calculations from computed tomography (CT) sections in 18 TOS and 16 control patients. Results: There was a strong correlation between the volume calculated by formula (4.79 ± 2.18 cm 3) and by mold (4.84 ± 1.58 cm 3), (R = 0.934, p = 0.001) in cadavers. The average volume measured in TOS patients (2.05 ± 0.32 cm 3) was significantly smaller than control patients (4.30 ± 1.85 cm 3 , p < 0.0001). There were excellent or good results in 14 patients whereas in 4 patients who had neurogenic TOS achieved fair results after surgery. In these 4 patients the average volumes of abnormal sides were close to the healthy sides. Conclusion: In our study, volume of interscalene space in TOS patients was statistically smaller than control group. Also, the volume was even smaller in patients with excellent or good results after surgery. In this respect, volumetric measurements from CT sections could be used in diagnosis and treatment selection in TOS patients.

Journal of the National Medical Association, Oct 1, 2018

Conflict of interest: The authors certify that they have no affiliations with or involvement in a... more Conflict of interest: The authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.

Journal of Obstetrics and Gynaecology

Türkiye Atom Enerjisi Kurumu, 2018

Journal of Turkish spinal surgery, 2015

Radiation Protection Dosimetry, 2020

In order to establish national diagnostic reference levels for mammography examinations, entrance... more In order to establish national diagnostic reference levels for mammography examinations, entrance skin air kerma, entrance skin dose and average glandular doses (AGDs) were calculated for a total of 25 624 cranio-caudal (CC) and mediolateral oblique (MLO) projections of 6309 patients for 40–49 and 50–64 age groups. The average entrance skin air kerma and entrance skin dose values for both age groups were found to be higher in MLO projections compared with CC projections. The minimum and maximum values of AGDs were determined as 0.4 and 7.9 mGy for both projections. The maximum numbers of AGDs for CC and MLO projections were calculated in the range of 1.1–1.5 and 1.6–2.0 mGy, respectively. The third quartile values of AGDs were calculated for each compressed breast thickness between 20 and 99 mm. The first national diagnostic reference levels of the country were established for each 10-mm compressed breast thickness in mammography examinations.

Interactive cardiovascular and thoracic surgery, Jan 16, 2018

The purposes of this study were to identify possible compression points along the transit route o... more The purposes of this study were to identify possible compression points along the transit route of the subclavian artery and to provide a detailed anatomical analysis of areas that are involved in the surgical management of the thoracic outlet syndrome (TOS). The results of the current study are based on measurements from cadavers, computed tomography (CT) scans and dry adult first ribs. The width and length of the interscalene space and the width of the costoclavicular passage were measured on 18 cervical dissections in 9 cadavers, on 50 dry first ribs and on CT angiography sections from 15 patients whose conditions were not related to TOS. The average width and length of the interscalene space in cadavers were 15.28 ± 1.94 mm and 15.98 ± 2.13 mm, respectively. The widths of the costoclavicular passage (12.42 ± 1.43 mm) were significantly narrower than the widths and lengths of the interscalene space in cadavers (P < 0.05). The average width and length of the interscalene space ...

Turkish Journal of Trauma and Emergency Surgery, 2017

BACKGROUND: This study aimed to investigate the role of inflammatory markers in decreasing negati... more BACKGROUND: This study aimed to investigate the role of inflammatory markers in decreasing negative appendectomy rate (NAR) based on their relation with findings of acute appendicitis (AA) on computed tomography (CT). METHODS: Ninety-two patients who underwent CT examination with suspected AA were included. We investigated the relation between CT findings of AA and laboratory inflammatory markers and also performed receiver operating characteristic (ROC) analysis to calculate cutoff values of inflammatory markers and CT findings of AA. Appendectomy cases were re-evaluated considering cutoff values to make the operation decision and NAR was recalculated. Chi-squared test was used to compare the actual and recalculated NAR. RESULTS: Cutoff values of appendiceal diameter, appendiceal wall thickness, and caecal wall thickness were 7.9, 2, and 2.3 mm, respectively, for the diagnosis of AA. Cutoff values of WBC , NLR, and CRP on ROC analysis were 7.47, 4.06 and 13, respectively, for the diagnosis of AA. When the actual and recalculated NAR (21.9% versus 9.1%) were compared, the difference was found to be almost significant (p=0.058). CONCLUSION: Inflammatory markers are not sufficiently powerful on their own to accurately diagnose AA. However, particularly in equivocal cases, proposed cutoff values may be helpful for accurate diagnosis and a lower NAR can be achieved.

The Laryngoscope, Jan 10, 2016

To analyze whether there is correlation between branching patterns of anterior inferior cerebella... more To analyze whether there is correlation between branching patterns of anterior inferior cerebellar artery/posterior inferior cerebellar artery (AICA/PICA) in cerebellopontine angle (CPA) area, as demonstrated by three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) magnetic resonance imaging (MRI) and 1) idiopathic sudden sensorineural hearing loss (ISSNHL) outcomes and 2) recovery of ISSNHL. We evaluated patients with idiopathic SSNHL for branching patterns of AICA/PICA in CPA area, as demonstrated by 3D FIESTA MRI. Sixty-eight patients with SSNHL (32 [47.1%] women; mean age 45.3 ± 14.6 [minimum-maximum: 18-77]) and 38 healthy volunteers [17 (44.7%) women; mean age 48.6 ± 14.0 (minimum-maximum: 26-81)] were included in this study. We evaluated patients for branching patterns and classified as type IA, IB, IIA, and IIB. Branching patterns were evaluated at the diseased side of the patients and both sides of the control group. Pretreatment and posttreatment au...

Medical Principles and Practice, 2016

Objective: To describe the relationship between atherosclerosis and hearing thresholds in prediab... more Objective: To describe the relationship between atherosclerosis and hearing thresholds in prediabetic patients with impaired fasting glucose (IFG) and to determine the efficacy of glycated albumin in predicting carotid artery atherosclerosis in patients with isolated IFG. Subjects and Methods: The study included 82 patients (aged 53.73-80 years) divided into two groups based on fasting glucose levels, the IFG group: 59 patients (32 females, 54.2%), and the normal fasting plasma glucose level group: 23 patients (12 females, 52.2%). Patients underwent audiological testing to determine hearing thresholds, and carotid intima-media thickness (CIMT) was measured using carotid artery Doppler sonography. Multivariate analyses were performed to determine whether or not the plasma glycated albumin levels could predict hearing loss and CIMT. Results: Patients in the IFG group (mean age: 59.8 ± 9.5 years) had higher hearing thresholds and pure-tone average scores (PTA) than those in the group w...